Pressure acid leaching of Caldag lateritic nickel ore: An alternative to heap leaching

Onal, Mehmet Ali Recai
Topkaya, Yavuz Ali
In this study, the leachability of Caldag lateritic nickel ore under high pressure acid leaching (HPAL) conditions was investigated. Several HPAL parameters were tested in a comparative manner since in many cases, the extraction efficiencies of Caldag ore sample were more than 90% for nickel and cobalt. After the optimization of the process parameters, it was found that 94.1% nickel and 94.0% cobalt could be extracted under the conditions of 325 kg sulfuric acid/tonne of dry ore, 250 degrees C leaching temperature, 1 h leaching duration and 100% - 1 mm particle size. Under these conditions, scandium also present in the ore was highly extracted into the pregnant leach solution. The results obtained were compared with the reported pilot plant testing results of atmospheric heap leaching by European Nickel PLC.


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Kul, A.; Topkaya, Yavuz Ali (Elsevier BV, 2008-06-01)
The main purpose of this study was to characterize and to extract germanium from the copper cake of Cinkur Zinc Plant. The physical, chemical and mineralogical characterization of the ground copper cake sample obtained from Cinkur showed that it was 84% below 147 pin containing 700 ppm germanium. The copper cake also contained 15.33% Cu, 15.63% Zn, 1.66% Cd, 1.33% Ni, 0.64% Co, 0.35% Fe, 2.62% Pb, 12.6% As, 0.18% Sb and 3.42% SiO2. The mineralogical analysis indicated the complex nature of the copper cake w...
Pressure leaching of Çaldağ lateritic nickel ore
Önal, Mehmet Ali Recai; Topkaya, Yavuz Ali; Department of Metallurgical and Materials Engineering (2013)
The purpose of this study was to investigate the process optimization of combined high pressure acid leaching (HPAL) and mixed hydroxide precipitation (MHP) route for the extraction of nickel and cobalt from Çaldağ lateritic nickel ore. In order to extract nickel and cobalt values into pregnant leach solution (PLS), several process parameters of HPAL including acid load, temperature, leaching duration and particle size were investigated in comparative manner at constant solid concentration and agitation spe...
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Gokcen, Fulya; Ozbelge, Tulay A. (Elsevier BV, 2006-10-15)
In this study, the efficiency of the integrated process was investigated in which the pre-ozonation step was followed by activated sludge process (ASP) in treating the aqueous Acid Red-151 (AR 151) solutions. The percent dye removal in the integrated process was found to be 47% for a pre-ozonation time of 30 min, instead of 25% in the singly ASP without pre-ozonation. The treatment efficiency of this process could be higher if the pre-ozonation time of 120 min yielding maximum enhancement of biodegradabilit...
Pressure leaching of Sivrihisar-Yunus Emre nickel laterites
Seçen, Berk; Topkaya, Yavuz Ali; Department of Metallurgical and Materials Engineering (2011)
The aim of this thesis study was to extract nickel and cobalt from Sivrihisar limonitic nickel laterite ore by high pressure acid leaching (HPAL) method under most economical operating parameters. Optimizing the conditions to yield a saleable quality mixed hydroxide product from the pregnant leach solution (PLS) was also investigated. To extract high amounts of nickel and cobalt from the laterite matrix; leaching duration, leaching temperature and sulfuric acid/ore ratio were studied at fixed conditions of ...
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Direct electrochemical reduction of porous SiO2 pellets in molten CaCl2 salt and CaCl2-NaCl salt mixture was investigated by applying 2.8 V potential. The study focused on the effects of temperature, particle size of SiO2 powder starting material and the behavior of cathode contacting materials during electrochemical reduction process. The starting materials and the electrolysis products were characterized by X-ray diffraction analysis and scanning electron microscopy mainly. The studies showed that smaller...
Citation Formats
M. A. R. Onal and Y. A. Topkaya, “Pressure acid leaching of Caldag lateritic nickel ore: An alternative to heap leaching,” HYDROMETALLURGY, pp. 98–107, 2014, Accessed: 00, 2020. [Online]. Available: